d-Galactose (d-Gal), when abnormally accumulated in the plasma, results in oxidative stress production, and may alter the homeostasis of erythrocytes, which are particularly exposed to oxidants driven by the blood stream. In the present investigation, the effect of d-Gal (0.1 and 10 mM, for 3 and 24 h incubation), known to induce oxidative stress, has been assayed on human erythrocytes by determining the rate constant of SO₄²⁻ uptake through the anion exchanger Band 3 protein (B3p), essential to erythrocytes homeostasis. Moreover, lipid peroxidation, membrane sulfhydryl groups oxidation, glycated hemoglobin (% A1c), methemoglobin levels (% MetHb), and expression levels of B3p have been verified. Our results show that d-Gal reduces anion exchange capability of B3p, involving neither lipid peroxidation, nor oxidation of sulfhydryl membrane groups, nor MetHb formation, nor altered expression levels of B3p. d-Gal-induced %A1c, known to crosslink with B3p, could be responsible for rate of anion exchange alteration. The present findings confirm that erythrocytes are a suitable model to study the impact of high sugar concentrations on cell homeostasis; show the first in vitro effect of d-Gal on B3p, contributing to the understanding of mechanisms underlying an in vitro model of aging; demonstrate that the first impact of d-Gal on B3p is mediated by early Hb glycation, rather than by oxidative stress, which may be involved on a later stage, possibly adding more knowledge about the consequences of d-Gal accumulation.

中文翻译：

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d-半乳糖通过人类红细胞中的Band 3蛋白降低阴离子交换能力。

d-半乳糖（d-Gal）在血浆中异常蓄积时，会导致氧化应激的产生，并可能改变红血球的体内平衡，尤其是暴露于血流驱动的氧化剂中。在本研究中，通过确定SO ₄ ^2-的速率常数，已测定了已知可诱导氧化应激的d-Gal（0.1和10 mM，分别孵育3和24 h）对人红细胞的作用。通过阴离子交换带3蛋白（B3p）摄取，这对红细胞的动态平衡至关重要。此外，已经验证了脂质过氧化，膜巯基氧化，糖化血红蛋白（％A1c），高铁血红蛋白水平（％MetHb）和B3p表达水平。我们的结果表明，d-Gal降低了B3p的阴离子交换能力，既不涉及脂质过氧化，也不涉及巯基膜基团的氧化，也不涉及MetHb的形成，也不涉及B3p表达水平的改变。d-Gal诱导的％A1c与B3p交联，可能是造成阴离子交换率变化的原因。目前的发现证实，红细胞是研究高糖浓度对细胞动态平衡影响的合适模型。显示了d-Gal对B3p的首次体外作用，有助于理解体外衰老模型的基础机制；证明d-Gal对B3p的第一个影响是由早期Hb糖基化介导的，而不是由氧化应激介导的，后者可能在以后阶段参与，可能增加了有关d-Gal积累后果的知识。